AC motors such as three-phase motors are gaining popularity in applications such as automotive, industrial, and HVAC (heat, ventilating and air conditioning). By replacing the mechanical commutator used in traditional motors with electronic devices, improved reliability, improved durability and small form factors are achieved. Additional advantages of three-phase motors include better speed versus torque characteristics, faster dynamic response, and higher speed ranges, as examples. Generally, an AC motor (e.g., a three-phase motor) has a controller that generates a pulse-width modulated (PWM) signal used to produce drive signals for power switches coupled to different phases of the motor. These PWM signals may determine the average voltage and average current supplied to the coils of the motor, thus controlling the motor speed and torque.
For closed-loop control of the AC motor, the status of the motor may be provided to a controller of the motor system, e.g., via a feedback path. For example, phase currents of the three-phase motor are measured and the measured values are sent to the controller, which generates the PWM control signals based on the measured values of the phase currents. Analog-to-digital converters (ADCs) are often used to convert analog signals (e.g., the phase current in each phase of the three-phase motor) into digital data in motor control applications.